DarknessAuthor
My guess is he will be calm and just bring up how the volturi will come to kill them or force her to become a vampire and if she does become a vampire then there are other downsides than just wanting blood and turning into a disco ball like not having kids, leaving her family, etc. Which I assume Edward and the others haven’t told her yet.
Add another conversation with Damon and Rosalie. Make it with how stupid Edward was saving Bella from the truck and then leaving by being mysterious. The stupidity that made Bella start to question what Edward is. Thus showing how much contempt Damon has on the Cullen family with them supporting Edward in every stupid thing he will eventually decide. Or something along those lines. Hope this is an idea you can use.